Duplex charge forming device



,A April 25, 1933. F. E. AsELTlNE I DUPLEX CHARGE FORMING DEVICE 4 sheetsheet l Filed Nov. 2, 1929 NMS I 3 Jrea' dselzine April 25, 1933. F. E. AsELTlNE DUPLEX 'CHARGE FORMING DEVICE 4 Sheets-Sheet 2 Filed Nov. 2. 1929 llllllnl..

April 25,'1933.

F. E. ASELTINE DUPLEX CHARGE FORMINQ DEVICE Filed Nov. 2, 1929 4 Sheets-Sheet 3 April 25, 1933.l F. E. AsELTlNE DUPLEX CHARGE FDRMING DEVICE Filed Nov, 2, 1929 4 Sheets-sheet 4 Patented Apr. 25, 1933 UNI'TED STATES PATENT OFFICE FRED E. ASELTINE, 0F DAYTON, OHIO, ASSIGNOR TO DELCO IERODU'C'IS CORPORATION,

OF DAYTON, OHIO, A CORPORATION' OF DELAWARE DUPLEX CHARGE romaine DEVICE This invention relates to charge forming devices for internal combustion engines, and more particularly to devices of this character which comprises a plurality of primary carburetors, each of which delivers a primary mixture of fuel and air to one of a plurality p, of secondary mixing chambers located adjacent the engine lintake ports, and in which the primary mixture is mixed with additional air under certain operating conditions.

An example of charge'forming device of this character is disclosed in the application of Fred E. Aseltine, Wilford H. Teeter, Carl H. Kindl and Frederick D. Funston, Serial No. 370,17 9, filed June 12, 1929.

The principal object ofthe present invention is to provide a novel charge forming device which is effective to secure equal distribution of the fuel charge to the various cylinders of multicylinder engines, particularly engines having more than four "cylinders.

According to the present invention, this object is attained by the provision of an air manifold having two entirely separate passages formed therein, each of which communicates with half of the cylinders, the groups of cylinders with which each passage communicates preferably having the same firing order. Tlie carburetor unit is provided'with a plurality of primary carburetors and in the specific embodiment disclosed herein, these are of the type shown in the above mentioned application, and each communicates with one of the outlet branches of the above manifold. The carburetor unit ,is provided with two separate air passages, one of which communicates with each of the air passages in the manifold and each of which is supplied with air from a main air chamber communicating with' the atmosphere through a single air inlet.

A partition is provided in the air chamberV which divides such chamber into two chambers or passages, each of which communicates with one of 'the aforementioned passages and also supplies air to a plurality of the primary carburetors ,in the manner hereinafter described, while the admission of air to this divided chamber is controlled by a single suction-operated valve having a slot therein which embraces the partition.

Further .objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a plan view of a charge forming device embodying this invention, said View being drawn on a smaller scale kthany the other views in order t0 show the entire structure.

Fig. 2 is a front elevation of the carburetor unit and one end of the associated manifold, the other end being broken oi as indicated.

Fig. 3 is a side elevation of the main carburetor unit viewed from theright in Fig. 1, and partly broken away to show further parts in section. I

Fig. 4 is a side elevation of the main carburetor unit viewed from the left in Fig. 1, and partly broken away to show certain parts in section.

Fig. 5 is a vertical `section on the line 5--5 of Fig. 1.

Fig. 6 is a horizontal section on the' lineA 6 6 of Fig. 5.

Fig. 7 is a horizontal section on the line, 7-7 of Fig. 5 looking upward.

Figs. 8 `and 9 are fragmentary sections showing the fuel supply passages.

Fig. 10 is a fragmentary, horizontal'section on the line 10-10 of Fig. 5, certain parts being omitted.

Fi 11 is a fragmentary plan view of the air c amber. l

` The device disclosed herein comprises a `main air manifold indicated in its entirety by the reference numeral 10. vThis main manifold is divided into two separate manifolds or headers 12 and'13, as indicated in Figs. 1 and 2, and each of these headers is provided with two outlet branches, the branches of the header 12 bein numbered 14 and 16 and those of the hea er 13 being numbered 18 and 20. These outlet branches is assembled, with two separate air passages 30 and 32 formed in the curburetor unit in the manner hereinafter described, and the outlet branches of the headers 12 and 13 communicate with groups of four cylinders of the eight-c linder engine, such grou s of cylinders re erably having the same ring order so t at the manifold in effect really divides the eight-cylinder engine into two four-cylinder engines, each of which is supplied with fuel mixture by a separate intake passage.

The carburetor unit com rises a main housing 34 having an attac ing flange 36 adapted to'be secured to the Iiange 24 by screws 38. An air inlet coupling 40 is secured in osition in an opening in the upper wall of t e housing 34 in any suitable way and may be connected with an air cleaner if desired. A casting 42, inA which the4 passages supplying fuel to the nozzles are formed, is secured b screws (not shown) to the lower wall of the main housing and a sheet metal fuel bowl 44 is held tight against anannular shoulder 46 on the housing by any suitable means such as a screw 48 extending into a depending portion of the castin 42. v

Fue is conducted from a main source of supply through a conduit (not shown) to -an angular fuel passage 50 formed in the wall of the main housing and communicat ing with a vertical passage 52 in the casting 42. Communicating with the latter passage is a restricted passage 54 within a nipple 56 screwed into the casting 42. A fuel valve full described, are formed. in the lower part of t e main housing 34, and communicating with the vertical portion of `the mixture passais 62 through orifices 64 are chambers 66, w 'ch may be designated fuel su plyl chambers for convenience. Fuel is admitted directly to these chambers by means hereinafterdescribed, and is mixed with a small quantity of air admitted to said chambers yby an opening 68, formed in a partition separatin the fuel chambers from a main air cham er as more fully described hereinafter. Communicating with each of the fuel supply chambers are nozzles 70, each of which is provided with a main fuel outlet 7 2 in the top of the nozzle and secondary fuel outlets 73 and 74 formed in the vertical wall of the nozzles close to the bottom of the said fuel supply chambers. The suction within the fuel supply chambers is sufficient to effect a flow of fuelfrom the main fuel outlet only when the engine is running at relatively high speed, while the secondary fuel outlets are effective to supply fuel at all speeds, and to supply all the fuel at relatively low speeds, when the suction is sulficient to lift the fuel in the nozzles only to a point between saidsecondary fuel inlets an the main fuel inlet, the fuel flowing from the former by the action of gravity.

Fuel is conducted from the float chamber to the nozzles through a vertical passage 80,

formed in the casting 42 and illustrated in Figs. 6 and 8. This passage communicates at its upper end with a horizontal channel 82, which communicates with a shortl vertical channel 84 connecting with a horizontal fuel canal 86, which is shown in plan in Fig. 6. The passage 86 extends an equal distance on both sides of the passage 84 and at its ends, communicates with two passages 88 arranged lat an angle thereto, the passages 88 communicating with the fuel nozzles directl The nozzles are positioned immediately a ove the ends of the passages v 88, so that the distance through which the fuel flows from the passage 84 to each nozzle isthe same, this construction being provided so that equal distribution is secured,

because the frictional resistance to the flow of fuel from the passage 84 to each nozzle and the vtime required for the fuel to reach each nozzle is substantially the same.

Fuel is suppliedto the vertical passage 80 at all times .throu h a calibrated plug A90, having a fixed or'ce therein and communicating direct with the fuel inthe fuel reservoir. A er a certain predetermined throttle movement', a valve 92, normally held closed by spring 94, is opened by means to be later described, to permit a flow of fuel from the reservoir 44 around said valve into a' bore 96, formed in the casting 42, and thence through a metering plug 98, screwed into the bore, to a horizontal passage 100,'which communicates with the passage 80, as shown in Fig. 4. Additional fuel is supplied b the above described passages to provide t e necessary quantity of fuel demanded by the engineA when operating at relatively high speeds.

A still further means for supplying additional fuel to the nozzles under certain conditions comprises a fuel port 102, controlled mitted through the port and flows throughv 'said bore 108 and a metering plug 110 screwed into said bore, into a vertical passage 112, communicating at lts lower Yend with the bore 108, and at its upper end with the horizontal passage 114, which connects with the passage 84.

The primary mixture passages are controlled by a single throttle valve 116, which extends across all of the passages and is provided With grooves 118, which are adapted to register with said passages, as fully described in the above mentioned, earlier application.

The fuel supply chambers 66 communicate with chambers 120a and 1205 which may for convenience be termed primary air chambers. These chambers and the fuel supply chalnbers 66 are separated from main air chambers 122@ and 1225 by means of a partition plate 124 and the chambers 66 are also separated from the vertical portions of the primary mixture passages by a vertical partition 126, which is a part of the main casting and on which the plate 124 is supported.` Othervertical partitions 128 separate the fuel supply chambers from each other and these partitions are also formed integrally with the main housing. All of the air admitted to the carburetor is supplied through the air inlet coupling 40 and is controlled by a lvalve 130 normally held against its seat 132 by a spring 134, which is received between the valve and a flange 136, projecting from a sleeve 138, slidable on asleeve 140, secured in the main housing in any desirable manner, and forming a guide for the valve stem 142 to which the valve 130 is secured. Secured to the lower face of the valve 130 is a sleeve 144, which surrounds the spring 134 and litswithin a sleeve 146, extending upwardly from the partition 124, previously described. These 154 projects through the wall of the housing f from the hub'150 and engages the lower side of the flange 136 while another arm 156 integral with the hub 150 is adapted to be connected to some form of operating connection extending to a point convenient to the operator of the vehicle so as to enable the operator to lift the flange 136 if desired.y The mechanism previously described, while not exactly the same as that shown in the earlier application abovereferred to, is very similar thereto and forms no part of the present invention.

vHeretofore, as in the above mentioned appli'cation, all theprimary mixture passages and secondary or auxiliary air passage have each been supplied with air froma single primary and secondary air chamber respectively. According to the present invention, however, the main air chamber is divided into the chambers 122@ and 1225 by vertical partition plates 160 and 161, which at their top are provided with projections 163, which fit in grooves 162 in the inner wall of the main housing, while below these projections,

the edges of the plates contact with the inner wall of the main housing. The inner edges of the plates 160 and 161 extend to the sleeves 144 and 146. A vertical partition 165 integral with the main housing, similarly divides the primary air chamber into the separate chambers 120@ and 1205. Each of the chambers 120@ and 1205 communicates with two of the fuel supply chambers 66, which supply a primary emulsion o'f fuel and air to two of the primary mixture passages 62, while the chambers 122a and 1225 communicate directly with secondary air passages 30 and 32 respectively, the passage 30 thus supplying air to the passage 26 and header 12, while the' passage 32 supplies air to the passage 28 and header 13. The air valve 130 is provided with slots 164 and 166 into which the partitions 160 vand 161 extend, the valve sliding on the partition as it moves up and down. It will be clear that the valve controls the admission of air to both ofthe chambers 122@ and 1225. The flow of air through the passage 30 is controlled by a manually operable air throttle 168, secured to a shaft 170, journalled in thek main housing and by a suction operated valve 172, secured to a shaft 174, which is also journalled in the housing and is arranged off center with respect to the valve 172. The flow through the passage 32 is controlled by a valve 176 also secured to the shaft 170 and a suction operated valve 178 secured to the shaft 174 so that similar valves in the two passages 30 and 32 operate together as a unit.` The operating mechanism for these valves will be described in detail hereinafter. `In addition to the air supplied through the primary. air chambers 120aA and 1205 to the primary mixture passages, the vertical portions of .these passages are constructed to communicate with the two air chambers 122cvl and 1225, twoof the primary mixture p air through the chambers 120a, 120?) and 66l communicatin therewith must necessarily Lbe relatively s ow. Because of the low vel5'locity of the air passing the fuel nozzles, there A is substantially no velocity head created at such nozzles under any operating condition, or at any operating speed. Air

is admitted through the opening 68 more rapidly than it can be exhausted through the orifice 64, hence there is substantially no difference in the pressure maintained on opposite sides of the partition plate 124. The suction at the fuel nozzles, therefore, is at all engine speeds substantially the static suction maintained in the chambers 122a, and 1226, yas determined by the s ring 134,` which controls the opening o the main air valve.

During operation at all engine s eeds below a certain predetermined spee for example, that .corresponding to a vehicular speed of 20-25 miles per hour on a lever, the mixture supplied to the engine bythe primary mixture passages is of properly combustible proportions and is conveyed to the engine without mixture with additional.

air in the secondary mixing chambers, to be described later. At higher engine speeds than this, the valves controlling the flow of air through the secondary air passages are opened to supply additional air and increase the quantity of mixture supplied to the engine. v The shaft 170, on which the valves 168 and 17 6 are secured, is operated by the primary throttle after said throttle has "made a certain amount of independent movement, subsequent to which movement the valves 168 and 176 are moved simultaneously therewith. For this purpose the primary throttle is provided with an operating arm 180, secured to the end of the throttle by means not shown herein, but fully disclosed in the above mentioned application.v The arm 180 is provided with a hole 182 in its free end inl which any suitable form of operating connection extending to av point convenient to the operator, is adapted to be secured. Secured to'the arm 180, by means of a screw 184, is an' arm 186 carrying a stop screw 188, adapted to engage a fixed stop, as' shown in the earlier application, to limit the closing vmovement of the throttle. By

adjusting the stop screw, the normal closed In view of this diii'erence position of the throttle may be regulated as desired' to determine the idling speed of the engine.

Secured to the other end of the primary throttle, in the manner disclosed in the above mentioned application, isan operating plate 190, to which a link 192 is pivotally connected by a screw 194. The upper end of the link is ivotally connected to a pin 196, projecting rom an arm 198, secured to the shaft 170. The pin 196 is received loosely within a slot in the end of the link 192 to prevent binding of the parts and the pin is normally held in the bottom of this slot by a spring 200, connecting said pin and a pin projecting from the link 192.4 The parts are so arranged that when the primary throttle is opened, the screw 194 moves in a clockwise direction and during the first part of its movement such screw moves in the arc of a circle, the center of which is the pin 196, so that while moving in this arc the arm 190 is ineffective to move the pin 196. This movement takes place duringr the first part of the opening movement of the primary throttle and after the latter has -moved through a predetermined distance, the screw 194 no longer moves in such an arc but its movement is effective to lift the link 192 and move the pin 196 in a clockwise direction opening the valves 168 and 17 6. Closing or counterclockwise movement of the primary throttle will move the link 192 downwardly and obviously move the valves 168 and 176 toward closed position.

The valves 172 and 178, which are secured to the shaft 174, are adapted to be opened entirely by engine suction, but until the manually operable valves 168 and 176 are opened, as previously described, the suction operated valves are held closed by a bifurcated lever 202, which is pivoted on a pin 204, projecting from the primary throttle. r[his lever is urged toward closed position to hold the suction operated valves closed by a s ring 206, connected to an arm 208, projecting from the biurcated lever and to the main housing, as shown in Fig. 4. In order to enable the closing of the valves 172. and 178 by the means above described, an arm 210 is secured in any desirable manner to the end of the shaft 174 and is pivotally connected at its free end to the bent 1in 212. the lower end of which is connected to a dash-pot piston to control the opening movement of valves 172 and V-17 8, in a man-v ner to be later described. This link is received between the two arms of theA lever 202 and the pin 214 on said link is engaged b v -`'one arm of said lever. whenever it is 125 moved in a counterclockwise ,direction-by the spring 206, closing thevalves 172 and" 17 8 and holding such valves closed during the first part ofthe opening movement of the throttle. In order to permit the open- 30 ing of the valves 172 and 178 by engine suction, it is obvious that the lever202 must be moved out of engagement with the pin 214 and this is accomplished by the throttle operating mechanism when the latter has made a predetermined amount'of opening movement. For this purpose a pin 216 is secured to the operating plate 190 and projects therefrom so as to engage one arm of the lever 202 as the plate is moved in a clockwise direction, rocking the lever downwardly and moving it out of engagement with the pin 216, as fully described in the earlier application above referred to.

On opening movement of the primary.

throttle or the valves 168 and 176, the suction effective on the air valve is increased and the latter is opened against the pressure of its spring to permit an increased flow of air past said valve into the chambers 122a and 122?) and thence into the passages 30 and 32. It has been found that during opening movements of said valve it will flutter if allowed to open freely and to prevent fluttering, a dashpot of conventional form is provided. This dashpot consists of a cylinder 220, formed 'in the casting 42 and a piston 222 cooperating therewith and secured to the lower end of the air valve stem 142 by a nut 224. Small orifices 226 are provided in the dashpotpiston and areadapted to be normally closed by a check valve 228, slidable on the valve stem immediately above the piston. An orifice 230 is formed in a plate 232, which is secured to the bottom of the casting 42 to close the above mentioned cylinder 220, and other cylinders formed in the casting 42. The dashpot is of substantially conventional construction and retards the opening of the air'valve to the'extent de' termined by the sizes of the orifices 226 and 230.

The check valve 228 is provided to p revent a tendency of the air valve to enrlch the mixture by gradually moving toward closed position because of the effect of engine pulsations at relatively low speeds.l

primary throttle and designed to temporarily supply additional fuel to the primary mixture passages, in the manner hereinafter described. It has also been found necessary in order to secure the desired enrichment to provide means for retarding the opening of the suction operated valves 172 and 178 whenever the valves 168 and 176 are opened. This is necessary in order to produce a suficient pressure differential between the i11- let and outlet ends of the prima mixture passages to create a velocity of Ebw therethrough great enough to transport the enriched primary mixture from the fuel supply chambers to the secondary mixing .chambers substantially instantaneously. The rimary mixture must pass 'through a consi erable distance and if the suction operated valves were permitted to open freely, an appreciable time interval would be required for the rich and relatively heavy primary mixture to travel through this distance, obviousl a greater time interval than that require for pure air-to travel from the manually operable valves 168 and 176 to the secondary mixing chambers. By retarding the opening of the suction operated valves, the time interval necessary for the primary mixture to reach the secondary mixing chambers is reduced, while `that necessary for the air to reach said chambers is increased until these intervals become sub-1 ."s'tantially equalized, with the result that the enriched primar mixture and secondary air reach the secon ary mixing chambers at substantially the same time.

In order to retard y the opening of the valves 172 and 178,'the link 212, hereinbefore referred to,-is pivotally connected at its inner end in any desirable way to a dashpot piston 236, which is slidable in a cylinder 238 formed in a casting 42 and closed at the bottom by the plate 232, reviously referred to. A valve cage 240 avin a passage 242 therethrough, is secured in t e plate 232 so that the passage will admit fuel to the cylinder 238 from the main fuel reservoir when a check valve 244, received in said valve cave isfunseated. Upward movement of this @teck valve is limited by the pin 24e positioned above the valve and it will be obvious that upward .movement of the piston 236 is substantially unretarded, as the check valve is then opened, but downward movement of the piston, which takes place on opening of the valves 172 and 178, is retarded to delay the opening of said valve.

In order to regulate the retarding elfect of the above described dashpot so as to retard the opening of the .valves to substantially the same extent for the same opening movement of the throttle regardless' of the position the valves may occupy when their opening movement begins, an auxiliary cylinder 248 is provided which is positioned in the casting 42 substantially adjacent the cylinder 238 and connected therewith by a passage 250v at the bottom of the cylinders, as shown in Fig. 7. Slidable .within the cylinder 248 is a piston 252, which is normally e c .it

held in the position shownin Fig. by a spring 254, received'between the pistonnnd t e top of its cylinder. On downward movement of the piston 238, the piston 252 l v 5 is lifted by the pressure effective on the bottom of said piston and the fuel in the cylinder above the piston is forced outof an orifice 256 near its'top, the rate of esca e of fuel through this orifice determining t e retarding effect of the dashpot on the valves y172 and 178. After the valves have completed any opening movement, the spring 254 forces the piston 252 downwardly until it assumes the position it occupied'at the 4be ning of the o ening movement of said va ves and the cy 'nder 248 is filled with fuel from the main fuel reservoir throu h the orifice 256 above referred to. It shou d be clear, therefore, that the piston 252 oclcupies the same positionwhenever an openin movement of the valves 172 and 178 ta es place and the retarding effectl of the dashpot on these valves must be substantially the same for every opening movement thereof following the same amount of throttle movement.

The pump for supplying additional fuel to the primary mixture passages is operated by the primary throttle during its opening .movementf This pump comprises cylinder 258, formed in thel casting 42 and a pistonV 260, Slidable therein. The piston is operated by a rod 262, pivotally connected to pin 216, which projects from the yoperating plate 190.

`The rod is not actually connected to the pump piston but the lower end of said rod is received insidef of a tube 264, projecting upwardly from the piston and is adapted to engage the piston when the parts' lare in 40 the position shown. in Fig. 4 with the throttle closed, the piston being held in this position by spring 266, which is received in thev linder below the piston 260. When the rottle is moved in a clockwise direction to open it, the rod 262 is'moved downwardly vand moves the piston correspondingly while on closing movements of the throttle, they piston 'is lifted by the spring as the rod moves/upwardly. The pump cylinder com- `|51" municates with a fuel delivery conduit 268,

formed in the bottom of the casting42 and communicating with the vertical passage 270, which at its upper end 'communicates with a horizontal passage 272, and is en- 55 .arged immediately. below such passage to receive a check valve 273, which cooperates with -a seat 275, to prevent theI return of fuel to the pump cylinder after each operation of th pump. The passage 272 supplies B0 fuel to an open well 274, communicating wlth the atmosphere through an opening sothat atmospheric pressure is main-4 tained in the well. Passages 278 conduct fuel from the well to vertical passages 280,

35 which communicate with restricted passages 282, formed in the wall of the main housing and communicating with the primary mix-A ture passages. Communicating with the passages 278 are vertical air passages 284 receiving air from the o enin 27 asnshown in Fi 6, and the ends of t e passages 278 are a o open' and communicate with the space above the fuel in the fuel reservoir 44,

so that air is-admitted to the passages 278 forming therein an emulsion of fuel and'ar which 1s carried into the primary mixture passages on any downward movement of the pump piston substantially in the same manner as described in the earlier copending ap- Y plication. Fuel flows from the well into the passages 278 by the action of gravity and is mixed with the air supplied thereto to form an-emulsion of fuel and air which is drawn into the by the suction t erein. Air is ,admitted through the various passages so that the suction in the fuel delivery conduit is never suiiicient to draw fuel from the pump cylinder and fuel can only be delivered to the mixture passages on operation of .the pump.

It will be noted that the rod 262 is provided with an arm 286 which has an ear 288 projecting therefrom so as to engage the fuel valve 92 asl the pump piston moves 1 downwardly.

The manually o erable valve `104 hereinbefore referredto, 1s provided primarily for the purpose of regulating the fuel supply in accordancewith seasonal variations, but may be opened or closed whenever it is deemed desirable. The means for opening such valve comprises a plunger 290, which is rotatable in the main housing and engages the top of the valve 104. The lunger 290 is provided with means- (not s own) for efprimary mixture passages ecting vertical movement of the plunger on `rotation thereof so as to open orclose the valve as desired.

The primary mixturepassages 62 communicate with primary mixture tubes 292, 294, 296, and 298, tubes 292 and 294 supplying fuel mixture tothe outlet branches of the header 12, while the tubes 296 and 298 supply primary mixture to the outlet.-

branches of the header 13. Thus, it willbe seen that two of the primary vmixture passages supply fuel to the outlet branches of cast in position in the manifold during the sections, and the bottom of the tubes being l substantially flat in these sections, the surface over which the fuel flows is considerably increasedV so thatA there is a greater tendency for evaporation and less condensation of the fuel on the wall of the tube. The

secondary mixing chambers may comprise any desirable means for straightening the flow of air past the ends of the primary mixture tubes and increasing the velocity of flow at such point. No means of this character is illustrated herein and any form of such device which has been used in earlier devices of this character may be employed'.

The construction of the device disclosed in this application is very similar to that disclosed in the' earlier case referred to, with the exception of the divided air chambers and plurality of secondary air passages in the carburetor units, the separate passages formed in entirely separate parts of the manifold, so arranged that each passage supplies combustible mixture to one of two groups of four cylinders of an eightcylinder engine separately and the present invention relates to these features.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow. l

What is claimed is as follows:

1. A charge forming device for a multicylinder internal combustion engine comprising a plurality of mixing chambers, means for supplying fuel to said mixing chambers, an air chamber for supplying air to said mixing chambers having a partition therein dividing said chamber into two passages eacli of which communicates with one of said mixing chambers, and a single" air inletadmitting air to both of said passages.

2. A charge forming device for a multicylinder internal combustion engine comprising a plurality of mixing chambers, means forsupplyingfuel to said mixing chambers, an air lchamber for supplying air to said mixing chambers having a partition therein dividing said chamber into two pas- I sages each of which communicates with one of said mixing chambers, a single air inlet admlttmg air to both of said air passages, and a suct1on operated valve in said inlet regulating the flow of air through both said air passages.

3. A charge forming device for a multicylinderv internal combustion engine comprising a plurality of mixing chambers, means for supplying fuel to said mixing chambers, an air chamber for supplying air to said mixing chambers having a partition therein dividing said chamber into two passages each of which communicates with one of said mixing chambers, a single air inlet admitting air to both said air passages, a suction operated valve in said inlet regulating the flow of air through both said air passages, and a slot in said valve in which said partition is received.

4. A charge forming device for a multicylinder internal combustion engine comprising, a' plurality of mixing chambers, means for supplying fuel and air thereto, a plurality of auxiliary air passages for supplying air to said mixing chambers, an air chamber supplying air to said auxiliary air passages, a partition in said chamber dividing it into two separate parts, each of which communicates with one of said passages, and a single air valve controlling the admission of air to both parts of said air chamber.

5. A vcharge forming device for a multicylinder internal combustion engine comprising,` a plurality of mixing chambers, means for supplying'fuel and air thereto, a plurality of auxiliary,A air passages for supplying air to said mixing chambers, an air chamber supplying air to said auxiliary air passages, a partition'in said chamber, dividing it into two separate parts, each of which communicates with one of said passages, a single air valve controlling the admission of air to both parts of said air chamber, and aslot in said valve adapted to receive said partition.-

6. A charge formingA device for a multicylinder internal combustion engine comprising, a plurality of mixing chambers, fuel inlets therefor, a primary air chamber for supplying .air to all of said. mixing chambers, .a plurality of auxiliary air passages for supplying air to said mixing chambers, a main air chamber for supplying air to said auxiliary air passages, and a partition dividing the main and primary air chambers into separate parts communicating with different auxiliary air passages and diiferent mixing chambers respectively.

7. A charge forming device for a multicylinder internal combustion engine coinprising a plurality of mixing chambers, fuel inlets therefor, a primary air chamber for supplying air to all of said mixing chambers, a plurality of auxiliary air passages for supplying air to said mixing chambers, a main air chamber for supplying air to said auxiliary air passages, a partition dividing cylinder internal combustion engine comprising a plurality of mixing chambers, fuel inlets therefor, a primary air lchamber for supplying air to all of said mixing chambers,

Y a plurality of auxiliary air passages for supplying air to said mixing chambers, a main air chamber for supplying air to said auxiliary air passages and to said primary air chamber, and a partition ldividing both the main and primary air chambers into separate parts, communicating with different auxiliary air passages and diiierent mixing chambers respectively.

9. A charge forming device for a multicylinder internal combustion engine comprising a plurality of primary mixing chambers, means admitting fuel thereto, a plurality of secondary mixing chambers into which said primar mixing chambers deliver a mixture of fuel and air, a plurality 'of auxiliary air passages'adapted to supply air to said secondary mixing chambers, a main air chamber through which air ilows to said primary mixing chambers and to said auxiliary air passages, a partition dividing said air chamber into separate parts communicating with different passages and a single air valve controlling the flow f air through Said chamber on both sides of the partition.

10. A charge forming device for a multicylinder internal combustion engine comprising a carburetor unit provided with means for forming azprimary mixture of fuel and air, a manifold receiving primary mixture from the carburetor unit and ada ted to csupply a combustible mixture to t e engine intake orts, a plurality of air' passages in the mani 01d each of which com- `municates with'only certain of said intake orts, a plurality of auxilia air passages 1n the carburetor( unit adapte to communicate with the air passages inthe .manifold and a single air inlet admitting air to said plurality of auxiliary air passages.

11. A charge formingdevice for multicylinder internal combustion engines comprising a carburetor unit provided with means for forming a primary mixture of :fuell and air, a manifold receiving primary -mixture from the carburetor unit and adapted to supply a combustible'mixture to the engine intake ports, a plurality of air passages in the manifold each of which communicates with only certain of said intake ports, a plurality of auxiliary air passages in the carburetor unitv adapted to communicate with the air passages in the manifold and' a single air valve controlling the admission of air to saidv plurality of air passages.

12. A charge forming device for multi-cylinder internal combustion engines comprising a carburetor unit provided with means for forming a primary mixture of fuel and f air, a manifold receiving primary mixture from the carburetor unit and adapted to supv ply a combustible mixture to the engine intake ports, a plurality of air passages in the manifold each ofwhich communicates with only certain of said intake ports, a plurality of auxiliary air passages in the carburetor unit adapted to communicate with the air passages in the manifold, a main air chamber in the\ carburetor unit supplying air to said plurality of auxiliary air passages, a partition in said air chamber dividing said chamber into separate parts each of ,which communicates with one of said auxiliary air assages, -an air valve controlling the 4admission 'of Vair tothe separate partsv of said air chamber and a slot -in said valve ada ted to receive the partiti n.

13. A c arge forming device formulticylinder internal combustion engines comprising a carburetor unit provided with a plurality of primary mixing chambers in' which a primary mixture of fuel and air is formed, a manifold having a plurality of secondary mixing chambers formed therein and adapted to supply a combustible mixture to the engine intake ports, means for conveying the primary mixture to saidV secondary mixing chambers, a pluralit of air passages in saidmanifold each` o which sup lies air to certain of said secondary mixing chambers only, a plurality of auxiliary air'passages lin the carburetor unit adapted to communicateA with the air passages in saidmanifold, a` rimary air chamber for supplying air to e primary mixing chambers, a main air chamber for supplying air to all of said .auxiliary air passages, a' partition dividing the mainand primary air chambers into separate partscommunicatin with diifere'nt auxiliary air passages an different primary mixin chambers respectively, and a single va ve; controlling the flow of air onboth .sides ofthe partition.

- 14. An intake-manifold for a multi-cyli'nder internal combustion *engine comprising a pflurality of outlet branches adaptedto communicate with the engine intake ports,

a plurality of 'air passages within the mani- 129 fold each of which supplies air tocertain of`said outlet branches only, a plurality of inlet ports each ofwhich admits air to one of said air passages, and means adapted to convey a prima mixture of'air and fuel to 125 the outlet branc es'of said manifold.

15. A charge forming device for a multicylinder internal combustion lengine comprising, a plurality of mixingchambers, means for supplying fuel-'to said mixing 130 iis A chambers, means for supplying air tosaid mixing chambers comprislng a plurality of separate passages so constructe that communication between any one of said passages 5 and some of said mixing chambers is prevented, and a common air inlet admitting air to all of said :air passages. l

16. A charge forming device for a multicylinder internal combustion engine comprising, a plurality of mixing chambers, means for supplying fuel to said mixing chambers, means for supplying air to said mixing chambers comprising a plurality of l separate passages so constructed'that communication between any one of said passages and some of said mixing chambers is prevented, and a single airv valve controlling admission of air to all of said air passages.

17. A charge forming device for a multicylinder internal combustion engine comprising, a -plurality of mixing chambers, means for supplying fuel to said mixing chambers, means for supplying air to said mixing chambers comprising a plurality of separate passages so constructed that communication between any one of said passages and some of said mixing chambers is prevented, a common air inlet supplying air to all of said passages, and a single suction operated air valve controlling the flow of air through all 'of said air passages.

18. A charge forming device for a multicylinder internal combustion engine comprising, a plurality of secondary mim'ng chambers, means for supplying a primary mixture of fuel and air thereto, means for supplying auxiliary air to said secondary mixing chambers, said means comprising a plurality of separate secondary air passages 40 so constructed that communication between any one of said passages and some of the secondary mixing chambers is prevented, and a single air valve controlling admission of air to all of said secondary air passages.

19. A charge forming device `for a multicylinder internal combustion engine comprising, a plurality of secondary mixing chambers, means for supplyinga primary mixture of fuel and air thereto, means for supplyin .auxiliary air to said secondary mixing c ambers, said means comprising a plurality of separate secondary air passages so constructed that communication between any one of said passages and some lof the secondary mixing chambers is prevented,

and a single air valve controlling the ad-l mission of air to all of said secondary air passages and to the primary mixture forming means.

In testimony whereof I hereto aliix my signature.

FRED E. ASELTINE. 

